An image-reading device includes a plurality of image sensors, a starting signal generator and a signal timing regulator. Each image sensor reads images on a pixel basis and generating an image signal indicative of the image. The image signal is an analog signal. The starting signal generator generates starting signals at every predetermined time period. A sampling period for sampling the image signal is set within the predetermined time period. In response to the starting signal sequentially inputted to the image sensors, the image sensors read the image until the predetermined time period is expired. The signal timing regulator delays an input timing at which the starting signal is inputted to the image sensor so that the sampling periods for the plurality of image sensors are different from one another.